Marking grids are used during medical imaging procedures to provide visual reference points on the resulting image. The marking grid contains a contrast agent that is visible on images produced by the imaging technology employed, for example, X-rays, computerized tomography (CT) scans and/or magnetic resonance imaging (MRI). Marking grids can be used to locate the position of internal structures in the body of a patient, such as abnormal tissues or tumors, relative to the reference marks on the image. In use, the marking grid is attached to the external surface or skin of a patient's body, and the patient and marking grid are exposed to imaging radiation. The contrast agent in the marking grid produces dots, lines, or other shapes on the image that can be used as reference points.
Marking grids are useful for locating the position on the surface of a patient where a biopsy needle should be inserted. The grids typically include a radiopaque material, arranged in strips, mounted on a radio translucent border or frame. The grids are typically placed on the skin of the patient and a cross section of the grid is visible on a CT scan. The technician can determine a position for insertion of a needle by viewing the grid pattern, visible on the CT scan at the patient's skin as a series of dots representing a cross section of the strips, and inserting the needle in the appropriate location relative to the grid pattern. However, one issue with prior marking grids is that the strips on the grids often blocked access to the appropriate location on the patients skin, requiring that the marking grid be moved in order to mark the location with a skin marker prior to inserting the biopsy needle.
The present invention provides a biopsy grid in which each individual reference strip can be easily removed by the medical technician without having to move the grid, which allows for precise positioning of the biopsy needle on the surface of the patient. The present invention also provides an improved manufacturing method for making marking grids, and improved materials for use in the radio-opaque strip material.
The following references may be relevant to the present disclosure: U.S. Pat. Nos. 7,086,172; 6,714,628; 6,356,621; 5,285,785; 5,052,035; 4,985,019; 3,547,121.